As it is well known, a MEMS device (micro-electro-mechanical system) is a micro device which integrates the mechanical and electrical functions in a silicon chip or die by using the lithographic techniques of micro manufacturing.
In particular, with reference to FIG. 1, a MEMS differential pressure sensor 100 is described which comprises a silicon die 101 formed by an annular portion 102 and a circular or squared membrane 103 coupled to the upper edge of the annular portion 102.
The lower edge of the annular portion 102 is connected to a protective package 104 of plastic, metallic or ceramic material by means of an adhesive layer 105.
The protective package 104 is formed by a housing, substantially cup shaped housing, which shows an internal cavity 106 wherein the die 101 is mounted. The protective package 104 is also provided with a passing opening 107. When the die 101 is mounted in the cavity 106, the annular portion 102 surrounds the passing opening 107, thereby the passing opening 107 realizes a first access gate of a first pressure P1 onto the lower surface of the membrane 103.
In a conventional way, the protective package 104 is realized through molding before the die 101 is glued inside the cavity 106.
The cavity 106 is then closet on top by a metallic or plastic cover 108 provided with an opening 109 for putting the cavity 106 in communication with the outside of the protective package 104.
In particular, this opening 109 realizes a second access gate for a second pressure P2 onto the upper surface of the membrane 103. The MEMS differential pressure sensor 100 is then able to measure differences of pressure between the first and the second pressure P1, P2.
Moreover, metallic pins 110 project from the protective package 104 for allowing the electric connection of the MEMS differential pressure sensor 100 with the outside of the protective package 104.
Connections 111 for electrically connecting the die 101 with the metallic pins 110 of the cavity 106 are realized though wire bonding, after the die 101 has been fixed in the cavity 106.
A protective coating layer 112, generally silicon gel, fills in almost completely the cavity 106.
In other known embodiments, also the cover 108 is formed through molding and coupled to the protective package 104 after that the MEMS differential pressure sensor 100 has been fixed in the cavity 106 and electrically coupled to the pins 111.
Although advantageous under several aspects, these embodiments of the assembled electronic devices comprising MEMS differential pressure sensor show the drawback of being cumbersome since the cavity 106 must be wide enough for housing the die 101 and allowing the alternative connection operations through wire bonding.
Therefore the manufacturing of these devices provides the following steps: manufacturing of the protective package 104 and of the cover 108, mounting and electric connection of the die 101 inside the protective package 104, mounting of the cover 108 on the protective package 104.
Since these process steps are not provided in the conventional process flow for the realization of integrated circuits cause a considerable increase of the costs of the final device.
The technical problem underlying embodiments of the present disclosure is that of devising an electronic device comprising MEMS differential sensor devices, having such structural characteristics as to realize this electronic device with manufacturing processes of conventional integrated circuits, overcoming the limits and/or drawbacks still limiting conventional electronic devices.